Drain filter



FIG. 1 is a diagrammatic perspective view of a drain filter.

FIG. 2 is a top plan view thereof, the bottom plan view being a mirror image of the top plan view; and,

FIG. 3 is a left side elevational view of the drain filter, the right side, front and rear elevational views being mirror images of the left side view. 

The ornamental design for a drain filter, as shown and described. 